Abstract: A radio system employs a method of controlling the transmitted power of a radio signal such that a minimum power level for efficient reception is maintained. Data is simultaneously transmitted between two radio stations using an error correction code. Each block of the code is accompanied by a power bit. The transmitted power bit is set high or low in dependence upon whether the number of errors in a sample of received blocks, as determined by processing of the received code, is equal to, above or below a predetermined threshold value. At the other station the received power bit is directed to a power control device and used to adjust the output power of the transmitter of that station by continuously variable slope delta demodulation.

Abstract: A device for use in an intermediate station of a radio-relay communications system comprises a package consisting of a trunk switch, a multiplexer, and a demultiplexer. The switch (48) has three TDM inputs, one of which is connected to the output of the multiplexer, and three TDM outputs one of which is connected to the input of the demultiplexer. The switch is non-blocking and is adapted to switch any input TDM channel to any selected output TDM channel, to enable, for example, a signal received in an incoming channel from an adjacent radio station to be selectively retransmitted to radio station or directed to one of the user terminals at the radio station.